Essential Oil Of Laurus Nobilis Research Articles

Chemical profile and inhibition of MDR bacteria by the essential oil of Laurus nobilis L. and its major compound 1,8-cineol

Laurus nobilis L. (Lauraceae), which is popularly known as laurel. This species is commonly employed in the food, cosmetic and pharmaceutical industries. The objective of this study was to evaluate the chemical composition and the antibacterial and modulatory potential of the essential oil of Laurus nobilis and the compound 1,8-cienol. The essential oil of L. nobilis leaves (OELn) was obtained by hydrodistillation and the chemical components were evaluated by mass spectrometry coupled with mass spectrometry. 1,8-cineol was obtained commercially. The antibacterial and modulating activity of antibiotics was performed using the microdilution method to determine the minimum inhibitory concentration (MIC). The present study reports In the chemical analysis, 1,8-cineol was evidenced as the major compound of OELn. It was observed in the antibacterial activity better performance of the tested substances compared to Gram negative bactéria, mainly for Pseudomonas aeruginosa and Escherichia coli . In the modulation tests, the results of the OELn modulatory action were better than the action of 1,8-cineol, where it can be concluded that the action of the essential oil is mainly performed by the association of its chemical substances. The new information obtained from present study could be helpful in developing OELn as a potential antibacterial agent in near future. • 1,8-cineol was identified as the major compound of OELn. • The better antibacterial activity of the tested substances was against Gram negative bacteria. • In the modulation tests, the results of the OELn modulatory action were better than the action of 1,8-cineol.

Component composition of essential oil shoots and leaves of Laurus nobilis L. Ukrainian origian

The aim of our work was to carry out a comparative analysis of the essential oils of shoots and leaves of Laurus nobilis L. Ukrainian flora and to determine the prospects for their use in pharmacy.
 Materials and methods. Raw materials for obtaining essential oil (shoots and leaves) of Laurus nobilis L. were harvested in November 2017 in the southern regions of Ukraine.
 By the method of chromatography-mass spectrometry using an Agilent Technology 6890N chromatograph, the component composition of 4 samples of essential oil of Laurus nobilis L. raw material was investigated and identified.
 The composition of the essential oil was identified by comparing the results with the data from the NIsT 02 mass spectra library (more than 174,000 substances).
 Results. Thus, in the studied series of the essential oil of the shoots, a similarity was observed both in the set of components and in the relative content of a number of individual compounds and compounds of structurally related groups. The content in these samples was dominated by 1,8-cineole (19.63 % of the amount and 12.93 % of the amount, respectively), α-terpinyl acetate (16.22 % of the amount and 16.03 % of the amount, respectively).
 In contrast to the series of the essential oil of the shoots, the component composition of the essential oil of the leaves of the two series was significantly different. In both studied series, only 3 compounds were identified that are common - these are aromatic compounds methyleugenol, trans-methylisoevgenol, and the sequiterpenoid caryophyllene oxide.
 Conclusions. Thus, a comparative analysis of the component composition of biologically active substances in the essential oils of shoots and leaves of the Laurus nobilis L. Ukrainian harvest showed the prospects for further pharmacognostic research of this plant as a source of medicinal raw materials

Antimicrobial effect of laurel essential oil nanoemulsion on food-borne pathogens and fish spoilage bacteria

This research aimed to apply nanotechnology for nanoformulation of Laurus nobilis essential oil (EO) by ultrasonic emulsification method and characterization of nano-form: particle size, viscosity, polydispersity index, thermodynamic stability, and surface tension. The antimicrobial activity of laurel EO nanoemulsion (LEON) and laurel EO was also investigated against a panel of ten food-borne pathogens and fish spoilage bacteria. The GC–MS analysis of EO revealed that 1,8-Cineole was the main volatile compound. According to disc-diffusion results, LEON was more effective against Gram-positive pathogen bacteria of Staphylococcus aureus and Enterococcus faecalis than EO. Laurel oil demonstrated a higher inhibitory effect against fish spoilage bacteria (6.19 to 18.5 mm). The MICs values of LEON and laurel EO ranged from 6.25 to >25 mg/mL and from 1.56 to >25 mg/mL, respectively. Nanoemulsion and oil exhibited the best bactericidal activity against Pseudomonas luteola. Therefore, LEON can be developed as a natural antimicrobial agent in food industry.

In vitro acaricidal activity of essential oil and crude extracts of Laurus nobilis, (Lauraceae) grown in Tunisia, against arthropod ectoparasites of livestock and poultry: Hyalomma scupense and Dermanyssus gallinae

The current study assayed the toxicity of Laurus nobilis essential oil and crude extracts obtained using solvents of increasing polarity (cyclohexane, acetone and ethanol), on two ectoparasites of veterinary importance, i.e., Hyalomma scupense and Dermanyssus gallinae.The major components detected in bay laurel essential oil were dominated by 1.8-cineole (46.56 %), α-terpinenyl acetate (13.99 %), sabinene (7.69), α-pinene (5.75), linalool (5.50), methyleugenol (5.36 %) and β-pinene (3.97). The highest total phenolic and flavonoids contents were present in the ethalonic extract of L. nobilis leaves at an amount of 152.88 mg gallic acid equivalents per gram of dry weight (GAE/g DW) and 21.77 mg quercetin equivalent per gram of dry weight (QE/g DW), respectively.In vitro acaricidal effects of essensial oil and crude extract of L. nobilis against H. scupense were ascertained by adult immersion test of engorged females (AIT) and larval packet test (LPT) compared with a reference drug amitraz.The essential oil exhibited strong acaricidal activity against tick engorged female and inhibition of hatching eggs. After 24 h of exposure, at the highest tested concentration (100 mg/mL) essential oil induced 90.67 % mortality of H. scupense larvae (LC50 = 10.69 mg/mL). Otherwise, essential oil exhibited high acaricidal activity compared to extracts, and among the extract, the ethanolic extract revealed the highest acaricidal efficacy (81.27 % female mortality).Results from mite contact toxicity showed that essential oil and extracts from L. nobilis were toxic to D. gallinae. Bay essential oil was both more toxic to mites, and faster in exerting this toxicity than other tested crude extracts. L. nobilis essential oil concentration leaded to enhance mortality of D. gallinae reaching the highest (100 %) mortality at 12 h with a concentration of 320 mg/mL. While, ethanolic extract acheived this rate after 24 h of exposure at same concentration. Cyclohexanic extract showed weak acaricidal activity.

Acaricidal activity of Mentha suaveolens subsp. timija, Chenopodium ambrosioides, and Laurus nobilis essential oils, and their synergistic combinations against the ectoparasitic bee mite, Varroa destructor (Acari: Varroidae)

The main objective of the present study was to evaluate under laboratory conditions the toxicity of essential oils (EOs) extracted from Mentha suaveolens L. subsp. timija (Briq.) Harley, Chenopodium ambrosioides L. and Laurus nobilis L. against Varroa destructor adult mites. Also, various combinations were prepared by mixing equal concentrations of any two and all three studied EOs and used to evaluate the combinational acaricidal effects of mixtures against adult Varroa mites. The GC/MS analysis indicated that the main chemical compounds of M. suaveolens subsp. timija EO were menthone (40.42%) and pulegone (19.22%), whereas C. ambrosioides EO is rich in α-terpinene (34.08%), isoascaridol (13.6%), p-cymene (10.95%), thymol (10.26%), ascaridole (10.25%) and carvacrol (7.75%). L. nobilis EO is mainly composed with 1,8-cineol (37.5%) and linalool (14.09%). The fumigation bioassays showed that the three tested EOs showed varroacidal toxicity, whereas no mortality has been observed on honey bees that were exposed to their higher concentrations. The highest acaricidal potency was observed with M. suaveolens subsp. timija (LD50 = 3.360 µl/Lair and LD90 = 7.300 µl/Lair). According to the combination index (CI) calculated by CompuSyn software, the ternary blend combination exhibited high synergistic effectiveness with a CI value of 0.343. All combinations have shown favorable dose reduction with DRI indexes greater than one. Our findings suggest that EO combinations tested could present a promising solution to reduce the effective doses of EOs and constitute a promising alternative to synthetic acaricides.

Introduction pages

Notulae Botanicae Horti Agrobotanici Cluj-Napoca (NBHA): The papers published in Issue 4, Volume 48, 2020 represent new exciting researches in different topics of life science, respectively in plant science, horticulture, agronomy and crop science. Among the interesting articles we invite you to find news about: Exploring Artemisia annua L., artemisinin and its derivatives, from traditional Chinese wonder medicinal science; A critical review on the improvement of drought stress tolerance in rice (Oryza sativa L.); Plantation forestry in Malaysia: an evaluation of its successes and failures since the 1970; Transcriptome analysis to identify genes involved in lignan, sesquiterpenoid and triterpenoid biosynthesis in medicinal plant Kadsura heteroclite; Molecular cloning and characterization of a lipoxygenase gene (CsLOX1) from cucumber; Genetic relationship of mungbean and blackgram genotypes based on agronomic and photosynthetic performance and SRAP markers; Callogenesis optimization of some globe artichoke [Cynara cardunculus var. scolymus (L.) Fiori] cultivars based on in vivo and in vitro leaf explants; Chemical composition and antimicrobial and antioxidant activities of Tunisian, France and Austrian Laurus nobilis (Lauraceae) essential oils etc. The new Impact Factor communicated by ISI Clarivate, June 29, 2020, is IF 2019 = 1.168 (position 149 of 234 journals, Q3 in Plant Sciences). New metrics in Scopus – Elsevier (June 22, 2020): CiteScore 1.40 (#43/84 in Horticulture); SJR 0.35 - Q2, #41/90 in Horticulture (SJR Scimago Journal).

Chemical composition and antimicrobial and antioxidant activities of Tunisian, France and Austrian Laurus nobilis (Lauraceae) essential oils

Essential oil (EO) of Laurus nobilis, from Tunisian, France and Austrian were screened for their chemical composition, antioxidant and antimicrobial activities and compared. GC-MS analysis showed that leaves of Tunisian L. nobilis had camphor (34.43%), 1,8-cineole (20.21%) and α-terpineol (7%) as major components. France and Austrian EOs had a high content of 1,8-cineole (45.8% and 43.4%, respectively) followed by bornyl acetate (13.8% and 17.7% respectively) and methyl eugenol (7.7% and 10.9% respectively). Antioxidant potential was measured by ABTS and DPPH tests. Tunisian L. nobilis EO showed greater radical scavenging by ABTS activity (IC50=44.8±0.1 mg/L) than the France and Austrian EOs (76.4±3.2 mg/L and 81.4±4.0 mg/L, respectively). However, for DPPH test system, French and Austrian EOs activities were excellent (IC50=176.1±5.1 mg/L and 236.3±2.9 mg/L respectively) then Tunisian L. nobilis EO (IC50=2859.7±99.0 mg/L). A good Antimicrobial activity was observed on the yeasts and fungi for all EOs. Tunisian laurel EO show a better antibacterial activity against gram-negative bacteria (Klebsiella pneumonial, E. coli and Salmonella enterica CMI: 0.004 mg/ml) than gram-positive ones (Bacilus subtilis, Staphylococcus aureus and Listeria monocytogenes CMI: 0.01 mg/ml). A significant antifungal activity of Tunisian EO was also observed against fungi and yeasts species (CMI: 0.004 mg/ml). France essential oil shows better activities against all organisms tested wail Austrian oil activity is more important against yeasts species tested and Mucor ramannianus (fungi). Chemical composition, antimicrobial and antioxidant activity of Tunisian L. nobilis essential oil, were different from that of France and Austrian and it give the opportunity for its uses in new pharmaceuticals and natural therapies of infectious diseases.

A synergistic interactions of Algerian essential oils of Laurus nobilis L., Lavandula stoechas L. and Mentha pulegium L. on anticholinesterase and antioxidant activities

This study aims at performing a chemical analysis of the essential oils of Laurus nobilis (LNEO), Lavandula stoechas (LSEO) and Mentha pulegium (MPEO) by GC-MS. The possible synergistic effects of their combinations on anticholinesterase and antioxidant activities were investigated. LNEO was dominated by 1,8-Cineole. Pulegone was found to be the major constituent of MPEO, while fenchone was the major component present, along with camphor in LSEO. LSEO was found to have the highest AChE inhibitor (17.73 ± 2.23 μg/mL) that matched the capacity of galantamine and the highest BChE inhibitor (1.61 ± 0.34 μg/mL) which is more than galantamine. A total of 13 combinations were obtained by mixing the EOs in binary and ternary mixtures at different ratios. CompuSyn software was used to allow automated simulation of synergism and/or antagonism. Of these, LSEO in very strong synergy with MPEO at a 2:1 ratio displayed 0.08 combination index (CI) on BChE. Even, the combination of LNEO with LSEO at different ratios showed synergistic effect against both enzymes. A significant antioxidant activity was displayed by LNEO. Of interest, LNEO is considered to interact very strong synergistically with either LSEO or MPEO in a 2:1 ratio in CUPRAC. The same combinations exhibited strong synergistic action in DPPH and ABTS . Summing up, the present work highlights the importance of the synergistic interaction of EOs as promising and ideal alternatives to the food and pharmaceutical industries as it leads to diminishing their effective doses consequently improving the safety profile with lower side effects while increasing their efficiency. • Essential oils of Laurus nobilis, Lavandula stoechas and Mentha pulegium were evaluated for their biological activities singly or in combination. • The oils showed an excellent anticholinesterase activity and remarkable antioxidant activity. • Synergistic interactions of binary and ternary essential oil combinations were proved.

Complete essential oils of Laurus nobilis inducing antinociceptive action by opioid mechanism in C-Reflex and spinal Wind-Up model in rat

The essential oil of Laurus nobilis L. was used to test their antinociceptive efficacy. It was applied intraperitoneally (i.p.) to rats subjected to a nociception test (C reflex and spinal wind-up). The results showed that the essential oil applied at higher doses (0.06 mg/Kg) causes a complete abolition of the spinal wind-up, while the C reflex was unchanged, indicating a clear antinociceptive effect. At lower concentrations (0.012 mg/Kg), there was a lowering in the wind-up by 85% within ten minutes of the essential i.p. oil application. Interestingly, there was an effect of naloxone (0.08 mg/Kg i.p.) When applied, a change occurs that almost entirely reversed the antinociception caused by the essential oil from Laurus nobilis. We conclude that there is a significant antinociceptive effect of the essential oil of Laurus nobilis subjected to electric nociception. In addition, it was observed that naloxone reversed the antinociceptive effect (windup) produced by Laurus nobilis.

The chemical, biological and thermal characteristics and gastronomical perspectives of Laurus nobilis essential oil from different geographical origin

Laurus nobilis (bay laurel) form Serbia (SRBL) and Russia (RFBL) were analyzed in order to establish the chemical profile, thermal properties and biological activity. The GC/MS analysis showed that α-pinene (31.97%) is principal compound in the RFBL followed by eucalyptol (27.95%) and α-terpineol (10.28%). In the case of the SRBL, eucalyptol (40.51%) is the most abundant compound followed by α-terpineol (15.46%), while α-pinene was found in much lower amount (4.45%). Thermal analysis showed that the evaporation process of both oils was complex process and took place in two phases. Moreover, results indicated that the SRBL evaporated slower at the higher temperatures than the RFBL. In order to assess biological activity, the antioxidant and antimicrobial activities were investigated. The SRBL was more potent antioxidant agent in the case of both assays (DPPH and total reduction capacity). In the case of the antimicrobial activity, the SRBL showed greater potential of antimicrobial activities toward all tested microorganisms, while RFBL was found to be effective against all the bacteria and yeast, but did not possess any inhibitory action against fungi. Results indicate that both oils may be used in the food and pharmaceutical industries as antioxidant and antimicrobial agent.

Composition and Antibacterial Effects of Laurel (Laurus nobilis L.) Leaves Essential Oil

In the present study, the chemical composition of laurel (Laurus nobilis L.) leaves essential oil (EO) and its antibacterial effect on common food and water-borne pathogenic bacteria were investigated. The results showed that 1.8-cineol (41.1 %), sabinene (6.96 %), α-pinene (5.94 %), humulene epoxide II (5.73 %), and α-terpinenyl acetate (5.72 %) were the main compounds in the Laurus nobilis leaves EO. The EO showed the highest (P < 0.05) antibacterial effect on Enterococcus faecalis (28.0 mm, zone diameter), followed by Escherichia coli O:157 H:7 (27.1 mm) and Salmonella pullorum (25.2 mm). Regarding MIC/MBC ratios, Laurus nobilis EO had a bacteriocidal effect on all tested food and waterborne pathogens except of Listeria monocytogenes.

Susceptibility of Tribolium castaneum to Laurus nobilis essential oil and assessment on semolina quality

Cereal production has always been an important component of Tunisian agriculture. However, insect pests are considered as a serious biosecurity threat to Tunisian cereals’ production and industry. Several methods such as fumigation have been used in storage. However, their use is controverted due to human and environmental worries. The main objective of this study was to introduce an ecologically safe method for managing the rust–red flour beetle, Tribolium castaneum. The insecticidal activities of Laurus nobilis have been extensively investigated. Therefore, the L. nobilis leaf essential oil chemical composition, and its insecticidal activity against T. castaneum adults were evaluated. Thus, a preliminary screening tests were designed to assess fumigant toxicity of Laurus nobilis essential oil against T. castaneum adults and to determine median effective concentrations (LC50 value). A second experiment was aimed to test the impact of spaces occupation with semolina and the storage period on essential oil effectiveness. T. castaneum adults were treated with the LC50 concentration and mortalities were assessed after 30, and 60 days of storage under 50% and 100% spaces occupied with semolina. Furthermore, the qualitative contamination of semolina by T. castaneum and the effect of essential oil on semolina characteristics and rheological dough properties were elucidated. Results indicated that the oil exhibited strong fumigant potentialities that depend on the exposure period and percentage of space occupation. The LT50 values for T. castaneum ranged from 70.48 h for 50% space occupation with semolina to 43.44 h for 100% space occupation with semolina. Moreover, we investigated the essential oil impact on semolina characteristics (protein, ash, gluten, and moisture) and rheological dough. Results indicated that the oil exhibited strong fumigant potentialities that depend on the exposure period and percentage of space occupation. It was also revealed that essential oil treatment slightly modified semolina characteristics but did not affect rheological properties that still conformed with ISO standards. The results of this study can be interested in further phytochemical and insecticidal activities of L. nobilis essential oil as alternative fumigants for control of stored semolina without negative effect on the quality of semolina.

Studying microwave assisted extraction of Laurus nobilis essential oil: Static and dynamic modeling

Microwave assisted extraction (MAE) is recognized as an efficient technique to obtain essential oils (EO) when compared with conventional processes; its efficacy, however, strongly depends on several processing variables. The aim of this work was to evaluate the effect of selected process variables on the extraction of bay (Laurus nobilis) leaves' EO by means of MAE, as well as to describe and simulate the extraction process by means of static and dynamic models. The effect of each process variable was evaluated through statistical analysis based on a response surface design, varying solvent to feed ratio (s:l, 1:1–1:4 g/ml), microwave power (P, 360–540 W), and stirring speed (s, 0–400 rpm). Optimal conditions for EO extraction were achieved when higher values of P (540 W) and s (400 rpm) were combined with the lowest value of s:l (1:1 g/ml). Selected polynomial dependency for modeling the static results, adequately explained the observed responses. From the dynamic analysis, the agreement of the second order equation with the experimental results confirms that the developed dynamic model describes the transient behavior of MAE of bay leaves’ EO. Studied variables and their interactions significantly affected (p < 0.05) not only energy requirement and EO yield, but also the extraction mechanism and model parameters.

Evaluation of antifungal and anti-ochratoxigenic activities of Salvia officinalis, Lavandula dentata and Laurus nobilis essential oils and a major monoterpene constituent 1,8-cineole against Aspergillus carbonarius

This investigation is performed to evaluate the antifungal and anti-ochratoxigenic activities of Salvia officinalis, Lavandula dentata and Laurus nobilis essential oils (EOs), and their major constituent 1,8-cineole. The evaluation of these activities was performed by two assays, contact assay with application of different concentrations of each tested EO as well as 1,8-cineole (0, 0.1, 0.2, 0.3, 0.4 and 0.5%) in Czapek Yeast Agar medium (CYA) and volatile assay by application of one concentration of each EO equal to 0.025% of CYA. The chemical composition of tested EOs was determined through gas chromatographic-mass spectrometry analysis and their antioxidant capacity was assessed by DPPH assay. Obtained results showed that L. nobilis EO exhibited better antioxidant activity (IC50=0.35±0.05mg/mL) than S. officinalis (IC50=11.12±0.09mg/mL) and L. dentate (IC50=14.03±0.16mg/mL) and it possessed the highest phenolic content (15.15 ± 1.64 mg gallic acid equivalent/g EO). Statistical analyses of volatile assay showed that L. nobilis EO inhibited the growth rate much more than L. dentata and S. officinalis with a percentage equal to 47.82, 37.92 and 31.71%, respectively, and reduced the production of OTA with a percentage of 88.87%. While, on contact assay L. nobilis and L. dentata EOs exhibited a higher antifungal and anti-ochratoxigenic activities than S. officinalis, with a minimum inhibitory concentration (MIC) of about 0.3, 0.3 and 0.5%, respectively. The MIC of 1,8-cineole (0.5%) was approximately double to that of L. nobilis and L. dentata EOs. Hence, its powerful biological activities were assured by the synergism between the major component and the other existing ones.

Larvicidal activity against Aedes aegypti of essential oil of Laurus nobilis leaves obtained at different seasons

Aedes aegypti is a mosquito and vector of dengue, chikungunya and Zika virus making it a serious global health problem. We aimed to evaluate the chemical composition of the essential oil (EO) of Laurus nobilis leaves obtained at different seasons and its A. aegypti larvicidal activity. The EO was obtained from fresh leaves by hydrodistillation. Larvicidal activity was determined by the larval immersion test. It was identified 37 EO chemical compounds and the major ones were 1,8-cineole and linalool. Seasonal variations affected EO larvicidal activity: spring LC50 was 0.41 mg/mL and LC99 0.77 mg/mL, autumn LC50 was 0.60 mg/mL and LC99 1.37 mg/mL, winter LC50 was 0.66 mg/mL and LC99 3.19 mg/mL and summer LC50 was 0.91 mg/mL and LC99 2.50 mg/mL. The EO extracted during spring showed the highest larvicidal activity on A. aegypti larvae. Our results present a new perspective of L. nobilis EO use as a larvicidal agent.

Bomba Rice Conservation with a Natural Biofilm.

The chemical composition of commercial Syzygium aromaticum, Cinnamomum verum, and Laurus nobilis essential oils as well as their antifungal activity against four pathogenic fungi isolated from Mediterranean rice grains has been investigated. Eighty nine compounds accounting for between 98.5 and 99.4% of the total essential oil were identified. The phenylpropanoids eugenol (89.37 ± 0.29%) and eugenol (56.34 ± 0.41%), followed by eugenol acetate (19.48 ± 0.13%) were, respectively, the main compounds in clove and cinnamon essential oils, whereas large amounts of the oxygenated monoterpenes 1,8-cineole (58.07 ± 0.83%) and α-terpinyl acetate (13.05 ± 0.44%) were found in bay leaf essential oil. Clove and cinnamon oils showed the best antifungal activity results against all tested fungi. Against Alternaria alternata, clove essential oil displayed the best antifungal effect, whereas against Curvularia hawaiiensis, cinnamon essential oil was more active. Both essential oils showed a similar antifungal effect towards Fusarium proliferatum and Fusarium oxysporum. In vitro studies in inoculated rice grains showed that clove and cinnamon totally inhibited pathogenic fungal development after 30 days of incubation. In vivo studies showed that eugenol used with a polysaccharide such as agar–agar formed a fine coat which wraps the inoculated rice grains, creating a natural biofilm and reducing the development of all pathogenic fungi (80–95%) for 30 days.

Exploitation of essential oil extracted from Tunisian Laurus nobilis for the development of PET antibacterial sutures

The main purpose of this study is the use of a Tunisian bio resource for the improvement of mechanical and physical properties of braided polyethylene terephthalate (PET) sutures. In this study, antibacterial PET sutures were developed using Tunisian essential oil of Laurus nobilis. A new lubrication process was proposed for this fact. The essential oil of L. nobilis was selected because of its antibacterial properties as well as analgesic, antiseptic, antiviral, and anti-infectious proprieties. Optimized extraction process of essential oil was also determined. Characteristics and cytotoxicity of extracted essential oil were also investigated. In order to study the impact of lubrication conditions on PET suture performances, mechanical properties and antibacterial effects of braided sutures were studied. The obtained results prove that sutures lubrication improves suture knot efficiency and leads to smoother surface. Developed sutures show also obvious antibacterial effect against Staphylococcus aureus ATCC 6538 G (+) colonies.

Chemical composition and Antimicrobial Activity of the Algerian Laurus nobilis Essential oil

The aim of this research is to determine the chemical composition and the antimicrobial activity of Algerian Laurus nobilis essential oil. The chromatographic analyses (CG/MS) have shown that the major components of Laurus nobilis essential oil are the 1.8 cineol (24,658%) and the linalol (18,563%). The Laurus nobilis essential oil has shown an antimicrobial activity against all the tested strains except the Pseudomonas aeruginosa which shown a strong resistance. The Minimum Inhibitory Concentrations (MIC), Minimum Bactericidal Concentrations (MBC) and Minimum Fungicidal Concentrations (MFC) have been determined by the agar dilution method, some micro-organisms were susceptible to the essential oils that have the MBC values between 1% and 0.03%. A fungicidal action has been obtained regarding the Candida albicans, a fungistatic one regarding the Saccharomyces cerevisiae, these results promise to get a scientific validation to the massive use of this species.

Chemical composition and fumigant activity of essential oils from six plant families against Sitophilus oryzae (Col: Curculionidae)

Within the framework of finding new fumigants, less toxic and environmentally friendly, in comparison with conventional fumigants, natural products and essential oils are considered to be alternative sources of potentially active compounds. In this context, the aim of the present study was the chemical analysis and the evaluation of fumigant toxicity against the adults of rice weevil Sitophylus oryzae of sixteen essential oils obtained from fourteen plant species. The essential oils of the species Apium nodiflorum, Bupleurum fruticosum, Crithmum maritimum, Liquidambar orientalis and Laurus azorica consisted mainly of monoterpene hydrocarbons. Oxygenated monoterpenes were the prevailing group of compounds in the essential oils of Laurus nobilis, Myrtus communis, Salvia fruticosa S. pomifera subsp. calycina, S. officinalis and Thymbra capitata. The essential oils of Cotinus coggygria, S. microphylla and Teucrium capitatum were rich in sesquiterpenes. The most active essential oils were those of T. capitata (LC50 = 3.4 μL/L air) and S. pomifera subsp. calycina (LC50 = 4.4 μL/L air) against S. oryzae adults. The essential oils of S. fruticosa, L. nobilis and S. officinalis were also found to be highly toxic (LC50 = 7.4–15.5 μL/L air). Most of the other essential oils tested exhibited moderate to low toxicities (LC50 = 17.7–37.9 μL/L air), while those of C. coggygria and S. microphylla did not exhibit any noticeable activity. Our results indicate that some essential oils, and in particular those of T. capitata and S. pomifera subsp. calycina might be promising fumigants for the control of important pests of stored grain such as the rice weevil S. oryzae.

β-Cyclodextrin Supramolecular Microcapsules and Antioxidant Activity of Laurus nobilis Essential Oil

Laurus nobilis essential oil (LEO) was isolated by microwave-assisted hydro-distillation in a yield of 2.7%. The obtained oil from China was analyzed by GC and GC/MS. The main components from the oil were terpinyl acetate (23.14%), followed by terpineol (5.83%), caryophyllene (5.27%), eucalyptol (5.25%), and methyl eugenol (5.25%). Supramolecular micro-capsules of β-cyclodextrin (β-CD), heptakis (2,6-di-methyl)- β-CD (DM-β-CD), mono[2-O-(2-hydroxyethyl)]-β-CD (HE-β-CD), and mono[2-O- (2-hydroxy-propyl)]-β-CD (HP-β-CD) with LEO were prepared and various affecting factors were examined in detail. Furthermore, the formation constants (Ka) and the thermodynamic parameters (ΔG, ΔH and ΔS) were determined in the ranges of 20-50°C. The results indicated that the stoichiometry of the LEO-β-CD supramolecular microcapsules was 1:1 (molar ratio), the Ka decreased with the increase of temperature, and the inclusion abilities were according to following order: β-CD> HE-β-CD > DM-β-CD > HP-β-CD. The antioxidant and DPPH free radical scavenging activity of LEO was higher than those of BHT and PG. But superoxide anion inhibitory activity was weaker than that of PG.